West Ham United manager Slaven Bilic has bemoaned individual errors as his side were beaten 4-3 at home by newly-promoted Bournemouth.
Carl Jenkinson was sent off for the hosts, while Callum Wilson struck a hat-trick to secure the Cherries first win in the top tier of English football.
"It went wrong from the start. We played a very bad first half," the Croatian told reporters.
"It is very hard to explain three of their four goals - you can't make errors like that at this level. They were more lively and more aggressive but you can't make those mistakes.
"It's not an alarming situation but we can't continue to play without more desire. We simply need a better mentality."
The 46-year-old will expect to see improvements in the Hammers's next fixture, away at Liverpool next Saturday.
